The neuropsychological, neurochemical, and neuropathological changes underlying the cognitive deficits that occur in some aged individuals and in the dementia of Alzheimer's Disease are not well understood. Because aged nonhuman primates also develop cognitive and neurochemical deficits and senile plaques, several groups of investigators have studies underway which use this model of the human disorders. These investigations raise important ethical issues, are expensive, and time consuming, and a conference is needed 1) to review and publicize the information being generated, 2) to define future directions, and 3) to foster multidisciplinary collaborations thereby assuring that optimal results will be obtained. To facilitate accomplishing these goals, experts who are pursuing complementary studies in aged humans and rodents will participate to encourage development of new approaches and to point out ways to avoid missing opportunities. Presentations by the faculty will be published, and a position paper will be developed and published that will outline current and future strategies.